Energy-based surgical instrument for grasping, treating, and/or cutting tissue

ABSTRACT

A surgical instrument includes first and second shaft members defining proximal and distal end portions and including handles at the proximal end portions thereof. A pivot member couples the distal end portions with a gap defined therebetween proximally of the pivot member. First and second jaw members extend distally from the shaft members, distally of the pivot member. A lockout bar is movable between an unlocked position, withdrawn from the gap, and a locked position, disposed within the gap. The handles are pivotable between spaced-apart and approximated positions to pivot the jaw members between open and closed positions. The handles are yawable between the approximated position and a yawed position to yaw the jaw members between the closed position and a cutting position. The gap provides clearance to permit yawing such that, when the lockout bar is disposed in the locked position, yawing of the handles is inhibited.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/493,612, filed on Sep. 12, 2019, which is a U.S. National StageApplication under 35 U.S.C. § 371(a) of PCT/CN2017/076429, filed on Mar.13, 2017.

FIELD

The present disclosure relates to surgical instruments and, moreparticularly, to energy-based surgical forceps configured to grasp,treat, and/or cut tissue.

BACKGROUND

A forceps or hemostat is a plier-like surgical instrument which relieson mechanical action between its jaws to grasp, clamp, and constricttissue. Energy-based forceps utilize both mechanical clamping action andenergy, e.g., electrosurgical energy, ultrasonic energy, light energy,microwave energy, thermal energy, etc., to affect hemostasis by heatingtissue to treat, e.g., coagulate, cauterize, and/or seal, tissue.Typically, once tissue is treated, the surgeon has to accurately severthe treated tissue. Accordingly, many energy-based forceps have beendesigned to incorporate a cutting mechanism that enables tissue to becut after treatment or where only tissue cutting is desired.

SUMMARY

As used herein, the term “distal” refers to the portion that is beingdescribed which is further from a user, while the term “proximal” refersto the portion that is being described which is closer to a user.Further, to the extent consistent, any of the aspects described hereinmay be used in conjunction with any or all of the other aspectsdescribed herein.

A surgical instrument provided in accordance with aspects of the presentdisclosure includes first and second shaft members each defining aproximal end portion and a distal end portion. Each of the first andsecond shaft members also includes a handle disposed at the proximal endportion thereof. A pivot member defining a pivot axis pivotably couplesthe distal end portions of the first and second shaft members with oneanother. A gap is defined between the distal end portions of the firstand second shaft members proximally of the pivot member.

The surgical instrument further includes first and second jaw membersextending distally from the distal end portions of the respective firstand second shaft members. The first and second jaw members arepositioned distally of the pivot member.

A lockout bar is movable between an unlocked position, wherein thelockout bar is withdrawn from the gap, and a locked position, whereinthe lockout bar is disposed within the gap.

The handles of the first and second shaft members are pivotable relativeto one another in directions perpendicular to the pivot axis between aspaced-apart position and an approximated position to pivot the firstand second jaw members relative to one another between an open positionand a closed position. The handles of the first and second shaft membersare further yawable relative to one another in directions parallel tothe pivot axis between the approximated position and a yawed position toyaw the first and second jaw members relative to one another between theclosed position and a cutting position. The gap provides clearance topermit yawing of the handles of the first and second shaft members suchthat, when the lockout bar is disposed in the locked position, yawing ofthe handles of the first and second shaft members is inhibited.

In an aspect of the present disclosure, the lockout bar is moved fromthe locked position to the unlocked position upon pivoting of thehandles of the first and second shaft members from the spaced-apartposition to the approximated position.

In another aspect of the present disclosure, the lockout bar isprogressively moved from the locked position towards the unlockedposition as the handles of the first and second shaft members areprogressively moved from the spaced-apart position towards theapproximated position.

In still another aspect of the present disclosure, the lockout bar istranslated along one of the first or second shaft members from thelocked position to the unlocked positions.

In another aspect of the present disclosure, the lockout bar is movedtowards one of the shaft members and away from the other shaft memberfrom the locked position to the unlocked position.

In yet another aspect of the present disclosure, the lockout bar iscoupled to a leaf spring disposed between the first and second shaftmembers. In such aspects, approximation of the first and second shaftmembers may urge the leaf spring proximally, thereby moving the lockoutbar from the locked position to the unlocked position.

In still yet another aspect of the present disclosure, the lockout bardefines a cantilever configuration engaged at a proximal end portionthereof to one of the shaft members. In such aspects, approximation ofthe first and second shaft members may urge a protrusion extending fromthe other shaft member into the lockout bar to thereby urge the lockoutbar from the locked position to the unlocked position.

In another aspect of the present disclosure, the lockout bar is coupledto a rotatable member at a proximal end portion thereof. The rotatablemember is rotatably coupled to one of the shaft members and configuredsuch that rotation of the rotatable member between a first position anda second position moves the lockout bar between the locked position andthe unlocked position.

In an aspect of the present disclosure, each of the first and second jawmembers defines a stepped configuration including an interior corner.Yawing of the first and second jaw members from the closed position tothe cutting position shears the interior corners relative to one anotherto cut tissue disposed therebetween. In such aspects, the interiorcorners may be chamfered at angles from about 70 degrees to about 80degrees or, more particularly, at angles of about 75 degrees.

In still another aspect of the present disclosure, the handles of thefirst and second shaft members define finger holes and include annularramped portions extending about a portion of the circumference of thefinger holes. The annular ramped portions are configured to facilitateyawing of the handles of the first and second shaft members.

In another aspect of the present disclosure, at least one of the jawmembers is adapted to connect to a source of energy for treating tissuegrasped between the first and second jaw members. In such aspects, thelockout bar is moved from the locked position to the unlocked positionupon initiation of the supply of energy to the jaw member(s).

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects and features of the present disclosure are describedhereinbelow with reference to the drawings wherein like numeralsdesignate identical or corresponding elements in each of the severalviews and:

FIG. 1 is a rear, perspective view of an energy-based surgical forcepsprovided in accordance with the present disclosure, with an attachmentmember thereof separated therefrom;

FIG. 2A is a transverse, cross-sectional view of jaw members of theforceps of FIG. 1, disposed in an open position;

FIG. 2B is a transverse, cross-sectional view taken across section line2B-2B of FIG. 1, wherein the jaw members are disposed in a closedposition;

FIG. 2C is a transverse, cross-sectional view of the jaw members of theforceps of FIG. 1, disposed in a cutting position;

FIG. 3 is a top, longitudinal, cross-sectional view of the areaindicated as “3” in FIG. 1;

FIG. 4A is a top, longitudinal cross-sectional view of the portion ofthe forceps of FIG. 1 illustrated in FIG. 3, wherein a lockout bar ofthe forceps is disposed in an unlocked position;

FIG. 4B is a top, longitudinal cross-sectional view of the portion ofthe forceps of FIG. 1 illustrated in FIG. 3, wherein the lockout bar isdisposed in a locked position;

FIG. 5 is a side view of the forceps of FIG. 1 including a lockoutmechanism provided in accordance with the present disclosure, and theattachment member thereof removed;

FIG. 6 is a side, partial cut-away view of the forceps of FIG. 1including another lockout mechanism provided in accordance with thepresent disclosure;

FIG. 7A is a side view of the forceps of FIG. 1 including yet anotherlockout mechanism provided in accordance with the present disclosure,with the attachment member thereof removed;

FIG. 7B is a transverse, cross-sectional view of the forceps of FIG. 7Ataken across section line 7B-7B of FIG. 7A, wherein a lockout bar of thelockout mechanism is disposed in a locked position;

FIG. 7C is a transverse, cross-sectional view of the forceps of FIG. 7A,wherein the lockout bar is disposed in an unlocked position; and

FIG. 8A—8D are perspective views, from either side thereof, of first andsecond handles of the forceps of FIG. 1 including yaw-facilitatingfeatures in accordance with the present disclosure.

DETAILED DESCRIPTION

Referring now to FIG. 1, an energy-based surgical forceps 100 providedin accordance with the present disclosure includes first and secondshaft members 110, 120 each having a proximal end portion 112 a, 122 aand a distal end portion 112 b, 122 b, respectively. An end effectorassembly 200 of forceps 100 includes first and second jaw members 210,220 extending from distal end portions 112 b, 122 b of shaft members110, 120, respectively. Forceps 100 further includes a pivot member 130pivotably coupling first and second shaft members 110, 120 with oneanother, and an attachment member 150 releasably engagable with theproximal end portion of one of the shaft members, e.g., proximal endportion 112 a of shaft member 110. Alternatively, attachment member 150may be permanently affixed to the corresponding shaft member, e.g.,proximal end portion 112 a of shaft member 110.

Shaft members 110, 120 are formed at least partially from anelectrically-conductive material such that electrosurgical energy may betransmitted therealong to and from jaw members 210, 220, respectively.Alternatively, shaft members 110, 120 may house conductors (not shown)configured to transmit electrosurgical energy to and from jaw members210, 220. Proximal end portions 112 a, 122 a of shaft members 110, 120,respectively, include handles 114, 124 defining finger holes 115, 125configured to facilitate grasping and manipulating shaft members 110,120. Proximal end portion 112 a of shaft member 110 further includes anengagement sled 113 configured to facilitate sliding of attachmentmember 150 onto and into engagement about proximal end portion 112 a ofshaft member 110. Proximal end portion 122 a of shaft member 120, on theother hand, includes an activation finger 123 a and an electricalconnection pin 123 b, the functions of which are detailed below.

Distal end portions 112 b, 122 b of shaft members 110, 120 form uprights116, 126 (see also FIG. 3) defining aligned pivot apertures 117, 127configured to receive pivot member 130 therethrough for pivotablycoupling distal end portions 112 b, 122 b of shaft members 110, 120 withone another. As a result of this configuration, handles 114, 124 aremovable relative to one another in directions substantiallyperpendicular to a pivot axis of pivot member 130, e.g., verticallygiven the orientation of forceps 100 in FIG. 1, between a spaced-apartposition and an approximated position to pivot jaw members 210, 220about pivot member 130 and relative to one another between an openposition (FIG. 2A) and a closed position (FIG. 2B).

With momentary reference to FIG. 3, uprights 116, 126 of distal endportions 112 b, 122 b of shaft members 110, 120, respectively, define agap “G” therebetween proximally of pivot member 130. This gap “G”permits handles 114, 124 to be further movable relative to one anotherin directions substantially parallel to the pivot axis of pivot member130, e.g., horizontally given the orientation of forceps 100 in FIG. 1,between the approximated position, wherein jaw members 210, 220 aredisposed in the closed position (FIG. 2B), to a yawed position, whereinjaw members 210, 220 are disposed in a cutting position (FIG. 2C).

Referring again to FIG. 1, attachment member 150 includes a housing 152configured for slidable positioning about and releasable engagement withproximal end portion 112 a of shaft member 110, a switch assembly 154disposed within housing 152 and including an activation button 155extending therefrom, an electrosurgical cable 156 extending proximallyfrom housing 152, a plug 158 disposed at the free proximal end portionof electrosurgical cable 156 to enable connection of attachment member150 to a source of energy (not shown), e.g., an electrosurgicalgenerator, a plurality of electrical lead wires (not shown) extendingthrough electrosurgical cable 156 and into housing 152, and first andsecond electrical contacts (not shown) disposed within housing 152. Thefirst electrical contact (not shown) is disposed in electricalcommunication with shaft member 110 to establish electricalcommunication between one or more of the plurality of electrical leadwires (not shown) and first jaw member 210, while the second electricalcontact (not shown) is positioned such that, in the first approximatedposition of handles 114, 124 of shaft members 110, 120, respectively,electrical connection pin 123 b contacts the second electrical contact(not shown) to establish electrical communication between one or more ofthe plurality of electrical lead wires (not shown) and second jaw member220. However, other suitable electrical connection arrangements are alsocontemplated.

Switch assembly 154 of attachment member 150 is positioned such that,upon movement of handles 114, 124 of shaft members 110, 120,respectively, to the approximated position, activation finger 123 a ofproximal end portion 122 a of shaft member 120 is sufficiently urgedinto contact with activation button 155 to actuate activation button155. One of more of the plurality of electrical lead wires (not shown)of attachment member 150 is coupled to activation button 155, thusenabling initiation of the supply of electrosurgical energy to jawmembers 210, 220 of end effector assembly 200 upon actuation ofactivation button 155 of switch assembly 154, e.g., for treating tissuegrasped between jaw members 210, 220.

With additional reference to FIGS. 2A-2C, end effector assembly 200, asmentioned above, includes first and second jaw members 210, 220pivotable relative to one another between the open position (FIG. 2A),the closed position (FIG. 2B), and the cutting position (FIG. 2C). Eachjaw member 210, 220 includes a body 212, 222 defining a firsttissue-contacting surface 214, 224 and a step 216, 226 extending fromthe respective body 212, 222 towards the other jaw members 210, 220 anddefining a second tissue-contact surface 218, 228, respectively. Steps216, 226 of jaw members 210, 220 are laterally offset relative to oneanother such that, in an aligned orientation of jaw members 210, 220,second tissue-contact surface 218 of jaw member 210 opposes a portion offirst tissue-contacting surface 224 of jaw member 220 and such thatsecond tissue-contact surface 228 of jaw member 220 opposes a portion offirst tissue-contacting surface 214 of jaw member 210. Further, firsttissue-contacting surfaces 214, 224 define greater widths as compared tosecond tissue-contacting surfaces 218, 228 such that the portions offirst tissue-contacting surfaces 214, 224 extending between steps 216,226 also oppose one another.

With reference to FIG. 2A, in the open position of jaw members 210, 220,jaw members 210, 220 are spaced-apart from one another and disposed inthe aligned orientation relative to one another, wherein secondtissue-contact surface 218 of jaw member 210 opposes a portion of firsttissue-contacting surface 224 of jaw member 220, second tissue-contactsurface 228 of jaw member 220 opposes a portion of firsttissue-contacting surface 214 of jaw member 210, and the portions offirst tissue-contacting surfaces 214, 224 extending between steps 216,226 also oppose one another.

Referring to FIG. 2B, in the closed position of jaw members 210, 220,jaw members 210, 220 are approximated relative to one another butmaintained in the aligned orientation. More specifically, secondtissue-contact surface 218 of jaw member 210 is approximated relative tothe opposing portion of first tissue-contacting surface 224 of jawmember 220 and second tissue-contact surface 228 of jaw member 220 isapproximated relative to the opposing portion of first tissue-contactingsurface 214 of jaw member 210. The opposing portions of firsttissue-contacting surfaces 214, 224 extending between steps 216, 226 arecloser to one another than in the open position (FIG. 2A) but remainspaced due to steps 216, 226. One or more stop members (not shown) orother suitable features may be provided to maintain a minimum distancebetween second tissue-contact surface 218 of jaw member 210 and theopposing portion of first tissue-contacting surface 224 of jaw member220 and between second tissue-contact surface 228 of jaw member 220 andthe opposing portion of first tissue-contacting surface 214 of jawmember 210 in the closed position.

Movement of jaw members 210, 220 between the open and closed positions(FIGS. 2A and 2B, respectively), may be effectuated in order to graspand/or manipulate tissue. With tissue grasped between jaw members 210,220 in the closed position thereof, electrosurgical energy may beconducted between jaw members 210, 220 to treat tissue graspedtherebetween, e.g., upon actuation of activation button 155 (FIG. 1).More specifically, electrosurgical energy is conducted between secondtissue-contact surface 218 of jaw member 210 and the opposing portion offirst tissue-contacting surface 224 of jaw member 220 to treat, e.g.,seal, tissue therebetween, and between second tissue-contact surface 228of jaw member 220 and the opposing portion of first tissue-contactingsurface 214 of jaw member 210 to treat, e.g., seal, tissue therebetween.Electrosurgical energy may also be conducted transversely across theportions of first tissue-contacting surfaces 214, 224 extending betweensteps 216, 226 to treat, e.g., seal, tissue disposed therebetween.

With reference to FIG. 2C, in the cutting position of jaw members 210,220, jaw members 210, 220 are offset relative to one another such thatmovement of jaw members 210, 220 from the closed position to the cuttingpositions results in shearing action between the interior corners 219,229 of steps 216, 226 to cut tissue disposed therebetween. Rather thanbeing squared off, it has been found that providing chamfered interiorcorners 219, 229 promotes consistent, effective tissue cutting. Further,chamfered interior corners 219, 229 reduce wearing, thus ensuringeffective and reliable tissue cutting, particularly in embodiments whereat least a portion of surgical forceps 100 (FIG. 1) is configured as asterilizable, reusable device. In such reusable embodiments, attachmentmember 150 (FIG. 1) may be a single-use, disposable component or mayalso be sterilizable and reusable.

Referring also to FIG. 2A, the angle (α) of chamfered interior corners219, 229 may, in embodiments, be from about 70° to about 80°; in otherembodiments, from about 72° to about 78°; in still other embodiments,from about 74° to about 76°; and, in yet other embodiments, about 75°.

Turning to FIG. 3, as noted above, uprights 116, 126 of distal endportions 112 b, 122 b of shaft members 110, 120, respectively, definegap “G” therebetween which is proximal of pivot member 130 to enablehandles 114, 124 (FIG. 1) to move between the approximated position,wherein jaw members 210, 220 are disposed in the closed position (FIG.2B), and the yawed position, wherein jaw members 210, 220 are disposedin the cutting position (FIG. 2C). More specifically, as handles 114,124 (FIG. 1) are moved from the approximated position to the yawedposition, uprights 116, 126, disposed proximally of pivot member 130,are moved towards one another, eliminating or reducing gap “G,” whilejaw members 210, 220, disposed distally of pivot member 130, arecorrespondingly moved laterally apart from one another from the closedposition (FIG. 2B) to the cutting position (FIG. 2C). Thus, gap “G”provides suitable clearance to enable yawing of handles 114, 124(FIG. 1) and, thus, movement of jaw members 210, 220 from the closedposition (FIG. 2B) to the cutting position (FIG. 2C).

Referring to FIGS. 4A and 4B, in conjunction with FIG. 3, inembodiments, forceps 100 includes a lockout bar 160 movable into and outof the gap “G” defined between uprights 116, 126 of shaft members 110,120. More specifically, lockout bar 160 is movable between an unlockedposition (FIG. 4A), wherein lockout bar 160 is removed from gap “G”between uprights 116, 126 to enable yawing of handles 114, 124 (FIG. 1)and, thus, movement of jaw members 210, 220 from the closed position(FIG. 2B) to the cutting position (FIG. 2C), and a locked position (FIG.4B), wherein lockout bar 160 extends between uprights 116, 126 and actsas a shim therebetween to eliminate or reduce the gap “G” such thathandles 114, 124 (FIG. 1) are inhibited from yawing, thereby inhibitingmovement of jaw members 210, 220 from the closed position (FIG. 2B) tothe cutting position (FIG. 2C). Various embodiments of lockout bars andmechanisms for moving the same between the unlocked and locked positionsare detailed below with reference to FIGS. 5, 6, and 7A-7C.

As illustrated in FIG. 5, in embodiments, a lockout mechanism 500 isproviding for use with forceps 100 that includes a lockout bar 560formed as a distal extension of a leaf spring 510. Leaf spring 510, morespecifically, includes a proximal foot 520 at the proximal end portion512 thereof, a bend 530 towards proximal end portion 512, and anelongated distal end portion 514 from which lockout bar 560 extendsdistally. Proximal foot 520 is engaged with shaft member 110 of forceps100. Leaf spring 510 extends from proximal foot 520 towards shaft member120 of forceps 100 such that bend 530 is positioned adjacent shaftmember 120. Elongated distal end portion 514 and lockout bar 560 extenddistally from bend 530 between shaft members 110, 120 of forceps 100.Leaf spring 510 of lockout mechanism 500 is biased towards a lockedcondition, corresponding to a locked position of lockout bar 560,wherein the free distal end of lockout bar 560 extends between uprights116, 126 of shaft members 110, 120 to inhibit handles 114, 124 fromyawing, thereby inhibiting movement of jaw members 210, 220 from theclosed position (FIG. 2B) to the cutting position (FIG. 2C) (see alsoFIG. 4B).

Prior to reaching the approximated position of handles 114, 124, e.g.,in the spaced-apart position of handles 114, 124 or positions betweenthe spaced-apart and approximated positions, leaf spring 510 of lockoutmechanism 500 is maintained in the locked condition, wherein the freedistal end of lockout bar 560 extends between uprights 116, 126 of shaftmembers 110, 120. As handles 114, 124 approach the approximatedposition, shaft member 120 is urged into leaf spring 510 such that bend530 of leaf spring 510 is pushed proximally, thus pulling the freedistal end of lockout bar 560 proximally. However, until theapproximated position is reached, the free distal end of lockout bar 560remains disposed between uprights 116, 126 of shaft members 110, 120,thus maintaining the locked condition of lockout mechanism 500. As such,in the locked condition of lockout mechanism 500, the user may grasptissue, effect blunt dissection of tissue, and/or otherwise manipulatetissue without applying energy thereto and without cutting tissue.

With additional reference to FIGS. 1 and 2A-2C, when it is desired totreat and/or cut tissue, handles 114, 124 may be further moved to theapproximated position, wherein an appropriate pressure is applied totissue grasped between jaw members 210, 220 and/or wherein anappropriate minimum distance between second tissue-contact surface 218of jaw member 210 and the opposing portion of first tissue-contactingsurface 224 of jaw member 220 and between second tissue-contact surface228 of jaw member 220 and the opposing portion of firsttissue-contacting surface 214 of jaw member 210 is maintained. Uponmovement of handles 114, 124 to the approximated position or an actuatedposition beyond the approximated position (while maintaining theappropriate pressure and/or appropriate minimum distance due to flexionof shaft members 110, 120), activation finger 123 a of proximal endportion 122 a of shaft member 120 is sufficiently urged into contactwith activation button 155 to actuate activation button 155 and initiatethe supply of electrosurgical energy to jaw members 210, 220 to treattissue grasped therebetween.

Upon reaching the approximated position, shaft member 120 is urgedfurther into leaf spring 510 such that bend 530 of leaf spring 510 ispushed further proximally, thus pulling the free distal end of lockoutbar 560 proximally to the unlocked positon, wherein the free distal endof lockout bar 560 is withdrawn from between uprights 116, 126 of shaftmembers 110, 120, corresponding to the unlocked condition of lockoutmechanism 500. In the unlocked condition, the gap “G” is defined betweenuprights 116, 126, thus enabling yawing of handles 114, 124 (see FIG.3). As such, only after tissue has been treated (in embodiments whereactivation button 155 is actuated in the approximated positions ofhandles 114, 124) or where handles 114, 124 are moved to theapproximated position just prior to initiation of tissue treatment (inembodiments where activation button 155 is actuated in the actuatedposition of handles 114, 124) is lockout mechanism 500 unlocked toenable tissue cutting.

With lockout mechanism 500 unlocked, as noted above, tissue cutting maybe effected by moving handles 114, 124 to the yawed position, such thatjaw members 210, 220 are moved to the cutting position, wherein interiorcorners 219, 229 of steps 216, 226 shear past one another to cut tissuedisposed therebetween (see FIG. 2C). Forceps 100 may further beconfigured such that handles 114, 124 are biased towards an alignedorientation relative to one another. As such, once tissue is cut and theyawing force on handles 114, 124 removed, handles 114, 124 return to theapproximated position, thus returning jaw members 210, 220 to the closedposition.

Turning to FIG. 6, another lockout mechanism 600 providing for use withforceps 100 includes a rotating member, e.g., a wishbone 610. Wishbone610 defines a first leg 620, a second leg 630, and an apex portion 640.Locking mechanism 600 further includes a housing 650, a lockout bar 660,and a biasing spring 670. Housing 650 houses biasing spring 670, aportion of wishbone 610, and a portion of lockout bar 660. Housing 650may be an extension of housing 152 of attachment member 150 (which, insuch embodiments, may incorporate at least some components of lockoutmechanism 600 therein), or may be separate therefrom.

Apex portion 640 of wishbone 610 is coupled to shaft member 110 offorceps 100, the free end of first leg 620 of wishbone 610 is coupled toa proximal end portion of lockout bar 660, and one end of biasing spring670 is coupled to first leg 620 of wishbone 610 between the free endthereof and apex portion 640. The other end of biasing spring 670 iscoupled to housing 650 distally of wishbone 610. Biasing spring 670 isconfigured as an extension spring and serves to bias first leg 620 ofwishbone 610 distally, thus biasing lockout bar 660 distally to thelocked position corresponding to the locked condition of lockoutmechanism 600 (see also FIG. 4B).

The free end of second leg 630 of wishbone 610 extends from housing 650towards handle 124 of shaft member 120. More specifically, second leg630 of wishbone 610 is positioned such that, upon movement of handles114, 124 to the approximated position or the actuated position, aprotrusion 680 extending from handle 124 contacts the free end of secondleg 630 and urges second leg 630 proximally. Proximal urging of secondleg 630, in turn, urges wishbone 610 to rotate proximally against thebias of biasing spring 670, thereby pulling first leg 620 of wishbone610 and lockout bar 660 proximally to the unlocked position. Lockout bar660, more specifically, is pulled proximally such that the free distalend of lockout bar 660 is withdrawn from between uprights 116, 126 ofshaft members 110, 120, corresponding to the unlocked condition oflockout mechanism 600. In the unlocked condition, the gap “G” is definedbetween uprights 116, 126, thus enabling yawing of handles 114, 124 (seeFIG. 3).

Similarly as with lockout mechanism 500 (FIG. 5), lockout mechanism 600enables tissue cutting only after tissue has been treated or wherehandles 114, 124 are moved to the approximated position just prior toinitiation of tissue treatment. With lockout mechanism 600 unlocked, asnoted above, tissue cutting may be effected by moving handles 114, 124to the yawed position, similarly as detailed above. Once tissue cuttingis complete and handles 114, 124 released, biasing spring 670 returnslockout mechanism 600 to the locked condition.

Turning to FIGS. 7A-7C, another lockout mechanism 700 is shown for usewith forceps 100 and includes a lockout bar 760 defining a cantileverconfiguration wherein the proximal end portion 762 of lockout bar 760 isengaged to shaft member 120 of forceps 100 and wherein lockout bar 760defines a free distal end portion 764. Lockout mechanism 700 furtherincludes a protrusion 780 extending from shaft member 110 of forceps 100towards shaft member 120 thereof.

Lockout bar 760 is biased towards the locked position, wherein, as shownin FIG. 7B, free distal end portion 764 of lockout bar 760 is disposedwithin the gap “G” (FIG. 7C) defined between uprights 116, 126 of shaftmembers 110, 120 of forceps 100. With free distal end portion 764 oflockout bar 760 disposed within the gap “G” (FIG. 7C), yawing of handles114, 124 is inhibited and, thus, movement of jaw members 210, 220 to thecutting position is likewise inhibited, similarly as detailed above.

Upon movement of handles 114, 124 to the approximated position or theactuated position, protrusion 780 contacts lockout bar 760 between theproximal and distal end portions 762, 764, respectively, thereof, andurges the free distal end portion 764 towards shaft member 120. In thismanner, free distal end portion 764 of lockout bar 760 is moved to theunlocked position, wherein free distal end portion 764 is withdrawn(towards shaft member 120), from the gap “G” defined between uprights116, 126 of shaft members 110, 120, corresponding to the unlockedcondition of lockout mechanism 700. In the unlocked condition, the gap“G” is defined between uprights 116, 126, thus enabling yawing ofhandles 114, 124 (see FIG. 3).

Similarly as with lockout mechanism 500 (FIG. 5), lockout mechanism 700enables tissue cutting only after tissue has been treated or wherehandles 114, 124 are moved to the approximated position just prior toinitiation of tissue treatment. With lockout mechanism 700 unlocked,tissue cutting may be effected by moving handles 114, 124 to the yawedposition, similarly as detailed above. Once tissue cutting is completeand handles 114, 124 are returned towards the spaced-apart position, thebias of lockout bar 760 returns lockout bar 760 to the locked position,corresponding to the locked condition of lockout mechanism 700.

Turning to FIGS. 8A-8D, in conjunction with FIG. 1, as noted above,proximal end portions 112 a, 122 a of shaft members 110, 120,respectively, include handles 114, 124 defining finger holes 115, 125configured to facilitate grasping and manipulating shaft members 110,120. As also detailed above, handles 114, 124 are configured to yawrelative to one another, in directions substantially parallel to thepivot axis of pivot member 130, between the approximated position,wherein jaw members 210, 220 are disposed in the closed position (FIG.2B), and the yawed position, wherein jaw members 210, 220 are disposedin a cutting position (FIG. 2C). In order to facilitate this yawing ofhandles 114, 124 and provide a more ergonomic feel, handles 114, 124, asdetailed below, may include asymmetric features that provide increasedsurface area into which the surgeon's fingers may be urged to yawhandles 114, 124.

More specifically, handles 114, 124 may include annular ramp portions1114, 1124 extending about a portion of the circumference of fingerholes 115, 125 and positioned at the pressure point locations where thesurgeon's finger, which extend through finger holes 115, 125, wouldapply pressure to handles 114, 124 to effect yawing of handles 114, 124.Annular ramp portions 1114, 1124 define areas of increased surface areato spread out the applied force and are angled to provide an opposingsurface against which the surgeon's fingers are urged, thus enablingmore ergonomic yawing and facilitating yawing.

While several embodiments of the disclosure have been shown in thedrawings and described herein, it is not intended that the disclosure belimited thereto, as it is intended that the disclosure be as broad inscope as the art will allow and that the specification be read likewise.Therefore, the above description should not be construed as limiting,but merely as examples of particular embodiments. Those skilled in theart will envision other modifications within the scope and spirit of theclaims appended hereto.

1-15. (canceled)
 16. A surgical instrument, comprising: first and secondshaft members each defining a proximal end portion and a distal endportion, wherein each of the first and second shaft members includes ahandle disposed at the proximal end portion thereof; a pivot memberpivotably coupling the distal end portions of the first and second shaftmembers; and first and second jaw members extending from the distal endportions of the respective first and second shaft members, wherein thehandles of the first and second shaft members are: pivotable relative toone another in directions perpendicular to a pivot axis of the pivotmember; and yawable relative to one another in directions parallel tothe pivot axis to yaw the first and second jaw members relative to oneanother.
 17. The surgical instrument according to claim 16, wherein agap is defined between the distal end portions of the first and secondshaft members.
 18. The surgical instrument according to claim 17,wherein the gap is disposed proximal to the pivot member.
 19. Thesurgical instrument according to claim 17, further comprising a lockoutbar movable between a locked position, wherein the lockout bar isdisposed within the gap, and an unlocked position, wherein the lockoutbar is withdrawn from the gap.
 20. The surgical instrument according toclaim 19, wherein the gap provides clearance to permit yawing of thehandles of the first and second shaft members such that, when thelockout bar is disposed in the locked position, yawing of the handles ofthe first and second shaft members is inhibited.
 21. The surgicalinstrument according to claim 19, wherein the lockout bar is moved fromthe locked position to the unlocked position upon pivoting of thehandles of the first and second shaft members from a spaced-apartposition of the handles to an approximated position of the handles. 22.The surgical instrument according to claim 19, wherein the lockout baris progressively moved from the locked position towards the unlockedposition as the handles of the first and second shaft members areprogressively moved from a spaced-apart position of the handles towardsan approximated position of the handles.
 23. The surgical instrumentaccording to claim 19, wherein the lockout bar is coupled to a leafspring disposed between the first and second shaft members.
 24. Thesurgical instrument according to claim 23, wherein approximation of thefirst and second shaft members urges the leaf spring proximally, therebymoving the lockout bar from the locked position to the unlockedposition.
 25. The surgical instrument according to claim 16, whereineach of the first and second jaw members defines a stepped configurationincluding an interior corner, and yawing of the first and second jawmembers shears the interior corners relative to one another to cuttissue disposed therebetween.
 26. A surgical instrument, comprising:first and second shaft members, each of the first and second shaftmembers including a handle disposed at a proximal end portion thereof; alockout bar movable between a locked position, wherein the lockout baris disposed within a gap defined between the first and second shaftmembers, and an unlocked position, wherein the lockout bar is withdrawnfrom the gap; and a pivot member pivotably coupling the first and secondshaft members and defining a pivot axis, wherein the handles of thefirst and second shaft members are: pivotable relative to one another indirections perpendicular to the pivot axis; and yawable relative to oneanother in directions parallel to the pivot axis.
 27. The surgicalinstrument according to claim 26, wherein the gap provides clearance topermit yawing of the handles of the first and second shaft members suchthat, when the lockout bar is disposed in the locked position, yawing ofthe handles of the first and second shaft members is inhibited.
 28. Thesurgical instrument according to claim 26, wherein the lockout bar ismoved from the locked position to the unlocked position upon pivoting ofthe handles of the first and second shaft members from a spaced-apartposition of the handles to an approximated position of the handles. 29.The surgical instrument according to claim 26, wherein the lockout baris progressively moved from the locked position towards the unlockedposition as the handles of the first and second shaft members areprogressively moved from a spaced-apart position of the handles towardsan approximated position of the handles.
 30. The surgical instrumentaccording to claim 26, wherein the lockout bar is coupled to a leafspring disposed between the first and second shaft members.
 31. Thesurgical instrument according to claim 30, wherein approximation of thefirst and second shaft members urges the leaf spring proximally, therebymoving the lockout bar from the locked position to the unlockedposition.
 32. The surgical instrument according to claim 26, wherein thelockout bar defines a cantilever configuration engaged at a proximal endportion thereof to one of the first or second shaft members.
 33. Thesurgical instrument according to claim 32, wherein approximation of thefirst and second shaft members urges a protrusion extending from theother of the first or second shaft members into the lockout bar tothereby urge the lockout bar from the locked position to the unlockedposition.
 34. The surgical instrument according to claim 26, wherein thelockout bar is coupled to a rotatable member at a proximal end portionthereof, the rotatable member rotatably coupled to one of the first orsecond shaft members and configured such that rotation of the rotatablemember between a first position and a second position moves the lockoutbar between the locked position and the unlocked position.
 35. Asurgical instrument, comprising: first and second shaft members having aproximal end portion and a distal end portion, each of the first andsecond shaft members having a handle disposed at the proximal endportion thereof; and first and second jaw members extending from thedistal end portions of the respective first and second shaft members,wherein the handles of the first and second shaft members are: pivotablerelative to one another in directions perpendicular to a pivot axis; andyawable relative to one another in directions parallel to the pivot axisto yaw the first and second jaw members relative to one another.